Influence of Cropping Systems on Root‐Rots of Tobacco1

Abstract

1. Tobacco grown every year on the same land with fertilizer only or with fertilizer and manure gave better yields than when grown in rotation with other crops, particularly corn and hay. 2. Tobacco when rotated with corn and hay showed decidedly poorer yields than when rotated with potatoes and onions. 3. Tobacco grown every year on the same land with fertilizer and a timothy cover crop was poorer than where grown similarly without a cover crop. 4. The decrease in yield caused by the timothy cover crop was not so great as that caused by hay and corn in the animal husbandry rotation. 5. Observations on black root-rot of tobacco showed it to be independent of crops grown in rotation, providing the soil was quite acid, below pH 5.95. 6. Brown root-rot of tobacco was found to be associated with the cropping systems, those leaving considerable residues in the soil being most stimulative to the brown root-rot and deleterious to the tobacco. 7. Both black and brown root-rot are apparently influenced by climatic or seasonal factors because there is a very decided variation in different years with the same treatment.